hey. I am sorry you are going through this. My ex (of 5 years) broke up with me last year. I thought I was going to die. It felt like I was burning alive, the pain was physical.
I know what it feels like to love someone who doesn't love you back (or at least who doesn't care about you).
I got hospitalized at a mental hospital and it sucked, I really thought I was never going to forget about him.
But I can tell you: this feeling is not going to last forever.
The physical pain goes away, this feeling of being betrayed somehow goes away. it might take some time, but it doesn't last forever. I promise you this!
Do not give up on your life because of some guy who doesn't know how to treat you right.
You can overcome this and live so many beautiful things with someone who truly knows your value.
Believe me

you deserve better
sorry I made any mistakes! my native language is portuguese.
anyway, I am here in case you need